RADIOLOGICAL INVESTIGATION

images processed by a computer, this investigation gives clear pictures of soft tissues which an ordinary x-ray test cannot show such as muscles, organs, large blood vessels, the brain and nerves. Most commonly used in examination of shoulder and ankle, it allows cross sectional imaging of soft tissue, calcium deposits and bone.

CT arthrography

Figure 4: Stress fracture - radioisotopic bone scan appearance

scans are particularly useful in the detection of

osteochondral lesions,

stress fractures and they give little

information regarding soft tissue (figure 4). CT scan

CT is also known as CAT scan (computed axial tomography). Using multiple x-ray

involves a dye which is radio-opaque being injected into a joint cavity. X-rays won’t pass though, so enabling character- istic pictures and ‘shadows’ to be highlighted in the final picture. CT is better than MRI where bony injury is suspected, and it also has a role to play in imaging facial fractures, whereas MRI is better at showing intracranial disease.

CT is useful in evaluation of the spine, fractures in small bones and fractures in anatomically complex areas of the body such as the ankle, foot or pelvis (figure 5).

MRI scans

An MRI scan uses a strong magnetic field and radio waves to create pictures of tissues, organs and structures inside the body. It is less accurate in defining bone detail than CT but better at detection of subtle soft tissue changes.

It is non

invasive and no ionizing radiation is involved.

It is useful in detection of

spinal disc pathology, evaluating soft tissue masses and bone marrow tumours.

Figure 5: CT ankle scan showing osteochondral defect

TABLE 1: X-RAY TERMINOLOGY AP

PA Lateral Oblique Flexion Extension Supine

Decubitus Cranial Caudal

16

Antero-posterior Postero-anterior

Projection taken with the central ray perpendicular to the midsaggital plane

Projection taken with the central ray at an angle to any of the body planes

Joint is radiographed while in flexion Joint is radiographed while in extension

Stress views Typically taken of joints held in a ‘stressed’ position. Test of stability Prone

Patient lies on their front Patient lies on the back Patient lies on their side Towards the head Towards the feet

Ultrasound scan Recent technical improvements have made ultrasound increasingly more accurate while providing significant

Figure 7: Ultrasound of achilles partial tear

Figure 6: MRI showing deposits in the cervical vertebrae (shown as black within the marrow) are compressing the spinal cord

Figure 8: A sagittal plain ultrasound scan, the arrows show the hamstring origin. The arrow heads show the trajectory of a 20 gauge spinal needle.

benefits over traditional modalities such as magnetic resonance imaging, particularly regarding cost, patient satisfaction, and ease of usage. Use of diagnostic ultrasonography for musculoskeletal conditions is growing. Large tendons can be visualised: again haematoma formation and calcification can be clearly shown. Real time use of ultrasound can also be helpful during active movement, for example in shoulder impingement. In addition to diagnosing, an ultrasound scan can guide a real time procedure such as a joint injection, a dry needling or a peripheral injection. Cheaper technology plus miniaturisation make ultrasound an increasingly useful option and portability makes this a great prospect for management in future.

sportEX dynamics 2008:15(Jan):15-17